Ask the Experts: Diesel engines

Q. I have a Golf GTD on order which should arrive soon. It is a six-speed manual. I have read conflicting reports on whether new cars need to be run in or not.

Ask the Experts: Diesel engines

19 August 2011Drive Team

Q I have a Golf GTD on order which should arrive soon. It is a six-speed manual. I have read conflicting reports on whether new cars need to be run in or not. I was just wondering what advice you would have for a new diesel motor as I am not planning on selling it in the near future?

Nick

A Ask 10 different experts and you'll get 10 different answers on this one. Most say that after the first start-up and bedding in of the engine, usually in the factory, you shouldn't have dramas driving the car normally, as long as all the clearances and tolerances of the engine are within specification.

But it is always best to err on the side of caution and follow the maker's recommendations. VW says a new engine needs to be run in during the first 1500 kilometres and warns that driving style will affect engine quality. The company says you should drive at moderate speeds for the first 1000 kilometres and avoid flooring the accelerator or running the engine at more than two thirds of its rev limit.

You also shouldn't tow. From 1000 kilometres to 1500 kilometres you can gradually increase how hard you drive the car.

Q Which four-wheel-drive and/or all-wheel-drive systems are suitable for serious off-road use? Conversely, which of the systems are likely to get you into trouble if you do go off-road into very slippery conditions.

Peter

A It really depends on what sort of off-roading you're doing. If you're looking at some outback touring, then many of the roads can be easily traversed with some decent ground clearance, good tyres and underbody protection. But if you're looking to tackle steep slopes, rugged rocks or soft sand or mud, you also need an off-road system that is up to the job.

A low-range system is good for hill climbing and taking very difficult obstacles slowly, although securely scaling down slippery slopes is helped in modern 4WDs by hill-descent systems that modulate the anti-lock brakes to regulate speed. Also look for things such as differential locks, which allow the drive to be locked between and across axles. With three diff locks, you have to get all four wheels stuck or spinning before the car will stop. Some modern cars use electronics to do a similar job to diff locks, with varying success. Keep in mind, too, that in really slippery conditions you will often need to turn off the stability-control system.

As for cars that could get you into trouble, the on-demand systems that engage 4WD only when needed can be too slow to react, while a small engine without low range can be a problem in situations when you need grunt.